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Shire Sends Hemophilia Gene Editing Prospects Back to Sangamo

There is no single race in gene therapy, or gene editing for that matter, more competitive than the one between companies trying to create treatments for hemophilia. And if one of its entrants, Sangamo Biosciences, is going to come out on top, it’ll likely have to do it without the help of Shire.

Sangamo Biosciences (NASDAQ: SGMO), a gene editing company based in Richmond, CA, said today that it’s restructured a wide-ranging alliance with Dublin-based Shire (NASDAQ: SHPG). Specifically, Shire has returned rights to Sangamo’s experimental programs for hemophilia A and B to the California company, and kept ahold of a prospective treatment for Huntington’s disease and another unspecified program. All rights to other targets that were part of the original deal in 2012 have also been handed back to Sangamo, the two companies said.

Sangamo didn’t disclose any specific financial details in the deal. Each company is paying the costs for its own programs, and each will get royalties on sales for the therapies it doesn’t own full rights to, up to a “maximum cap.” Shire still has a right of first negotiation to re-acquire the hemophilia programs in the future.

Sangamo said that the two companies made this decision to focus on their respective areas of expertise. For Shire, that’s rare diseases like Huntington’s. Indeed, Sangamo said that the change will enable it to “accelerate the development” of its hemophilia A and B programs. Sangamo said that it’ll file papers by the end of the year to begin the first trial for its hemophilia B treatment.

Still, as I wrote earlier this year, a super competitive race has taken shape to try to develop long-lasting—if not curative—treatments for hemophilia using gene therapy. Hemophilia was one of the first diseases targeted in experiments with gene therapy, a method of delivering a healthy gene into a cell to replace a faulty or missing one. Yet nonetheless it’s taken a few decades and counting to make it work. Problems with the viral “vectors” used to deliver new genes into the body, and the immune response against those vectors, have proved a high hurdle. This recent editorial in Nature, for instance, details the balancing act companies are performing in trying to develop a safe, long-lasting treatment that doesn’t get shut down by the immune system.

Even now, despite all of the scientific progress that’s been made over the years, only a few treatments are in early clinical testing. Yet the allure of a potentially curative treatment for hemophilia—currently managed by frequent, expensive injections of drugs that help clot blood—has attracted no fewer than seven groups trying to use either gene therapy, or, in Sangamo’s case, gene editing. The entrants: Dimension Therapeutics/Bayer, Spark Therapeutics/Pfizer, Biogen (NASDAQ: BIIB), Baxalta, UniQure (NASDAQ: QURE), Sangamo, and BioMarin Pharmaceutical (NASDAQ: BMRN). The are some technical differences between all of the gene therapy players in the field. Some are using different types of adeno-associated virus and lentivirus vectors, which may elicit different types of immune responses and each have their purported strengths and weaknesses. Others are delivering different types of genes with these vectors. Baxalta and Spark, for instance, are using mutant therapeutic genes meant to clot blood much faster than normal—yet may produce unpredictable results.

One potential drawback of gene therapies using adeno-associated virus is that they may have to be repeated at regular intervals. Sangamo’s treatment would use zinc finger proteins to, in theory, create a permanent fix by making genetic corrections that would be passed on to other cells.

Ben Fidler is Xconomy's Deputy Biotechnology Editor. You can e-mail him at bfidler@xconomy.com Follow @benthefidler